Bladder cancer is among the five most common malignancies worldwide. Bladder cancer cases for 2010 were estimated at 67,160, with deaths estimated at 13,750 in the U.S. alone (A. Jemal et al., Cancer Statistics, 2010 CA: A Cancer Journal for Clinicians 60, 277-300, 2010). When detected early, the 5-year survival rate is approximately 94%; thus timely intervention can dramatically increase the probability of patient survival. At present, more than 80% of bladder tumors are non-invasive papillary tumors (pTa or pT1), but the remaining fraction exhibit muscle invasion at the time of diagnosis and have a much less favorable prognosis.
While radical surgery is required for muscle invasive disease, non-muscle invasive tumors can be treated more conservatively by transurethral resection of the tumor, with or without intravesical therapy; however, more than 70% of patients with early-stage disease will have a recurrence during the first two years after diagnosis, making bladder cancer one of the most prevalent of all cancers. If left untreated, these initially non-invasive lesions can progress to being muscle-invasive (F. Millan-Rodriguez et al., J. Urol. 164, 680-84, 2000). The recurrence phenomenon of bladder cancer means that patients require strict surveillance at least yearly. For quality of life and positive clinical outcome, the timely detection of disease recurrence is as important as the initial diagnosis.
The current primary diagnostic approach is cystoscopy coupled with voided urine cytology (VUC). Cystoscopy is an uncomfortable, invasive procedure associated with significant cost and possible infection and trauma. VUC remains the method of choice for the non-invasive detection of bladder cancer; yet, while the assay has good specificity, the sensitivity is suboptimal, especially for low-grade and low-stage tumors (D. S. Kaufman et al., Lancet 374, 239-49, 2009; D. Trivedi and E. M. Messing, BMC Urol. 9, 13, 2009).
A number of diagnostic protein markers for urinalysis have been developed commercially, but single biomarker assays lack adequate power to replace VUC or reduce the need for repeated cystoscopy. This is not surprising, given the redundancy of signaling pathways, the cross-talk between molecular networks, and the oligoclonality of tumors. Embodiments of the present invention provide identification of alternative biomarkers for detection of bladder cancer in non-invasively obtained material, which provides a desirable genome-wide analytical strategy.